复合双压电层FBAR的建模与仿真

Modeling and Simulating of Complex Double Piezoelectric Layers’ FBAR

在复合单压电层薄膜体声波谐振器(FBAR)的基础上,提出了一种新型的复合双压电层FBAR,它可以大大提高压电材料选择的灵活性。通过建模得到该结构的输入阻抗解析表达式,据此进行了仿真分析。仿真结果表明,基模谐振频率随双压电层结构中的较高声速压电膜的厚度所占比率的增加而加速增大,而相对带宽随较高机电耦合系数的压电膜的厚度与较低机电耦合系数的压电膜的厚度比的增加逐渐增加,并且复合双压电层FBAR出现了单压电层时所没有的模式。

Based on complex single piezoelectric layer＇s film bulk acoustic resonator （FBAR）, a new kind of complex double piezoelectric layers＇ FBAR is proposed. This structure can greatly improves the flexibility of the selection of piezoelectric materials for FBAR. The analytical expression of input impedance is derived and simulated. The results of simulation show that： 1） the resonant frequency of basic mode increases significantly with the thickness ratio of the piezoelectric layer with higher acoustic speed to the whole thickness of double piezoelectric layers, 2） the relative bandwidth increases with the thickness ratio of the piezoelectric layer with higher electromechanical coupling coefficient to that with lower electromechanical coupling coefficient, and 3） some modes can be found in double piezoelectric layers＇ FBAR but not in the single layer＇s FBAR.